1. Field of the Invention
The present invention relates to the bolting of doors, and, more particularly, to an apparatus which is particularly suited for keeping a door firmly bolted shut for a prolonged period of time and which will make such a bolted door resistant to the efforts of burglars and vandals to open it.
2. Description of the Prior Art
It is often desired to keep a door firmly shut for a prolonged period of time in such a manner that it will be resistant to the efforts of vandals and burglars to open it. For example, many public housing projects contain apartments which are vacated. When such an apartment is empty, it is desirable to keep the entrance to it firmly shut, so as to prevent vandals from entering and destroying property and to prevent burglars from entering and stealing fixtures or other items of value. Because ordinary locks are often found insufficient to prevent vandals and burglars from entering such apartments, it has been a practice in some housing projects in which apartments have metal frames and metal covered doors to spot weld the metal door surfaces to the metal frames in order to prevent undesired entrance through such doors. Although this method is highly successful at preventing unwanted intrusion, it unfortunatly damages the doorframes with which it is used.
Besides the spot welding method of securely shutting a door, mentioned above, the prior art has many other means for keeping doors shut. Unfortunately many of them are either unsuitable or insufficient for use in an environment such as that which occurs in certain public housing projects, in which vandals or burglars often use devices such as sledge hammers and crow bars in their efforts to obtain improper entrance through locked doorways. For example, U.S. Pat. No. 3,819,216, issued to Richardson, discloses a device for holding a door shut which comprises a bar designed to fit snugly against the doorjambs of a doorframe and against one broad side of a door placed in that doorframe. This bar has legs which are designed to fit into channels contained within brackets mounted by bolts that extend through the door, so as to hold the bar firmly against the door. The bar has doorjamb catching portions which prevent the door from being opened once the bar is in place. One disadvantage of this door bolting scheme is that its use of bolts which extend through the door results in permanent alteration of the door and requires considerable time and effort in installation.
Another device for holding a door shut is disclosed in U.S. Pat. No. 3,980,328, issued to Pearson. This patent discloses a flat bar, two brackets at each side of the doorframe for holding the bar across the door over its doorknob, and a doorknob grabbing structure attached to the bar for hooking on to the doorknob and holding it so that the door cannot be opened. Although this device has the advantage that it does not require any alteration of the door to which it is attached, it has the disadvantage of requiring that braces be attached to the doorframe with which it is used, and it also would appear to have the disadvantage of being relatively easily broken by burglars or vandals.
U.S. Pat. No. 3,919,807, issued to Mefford, discloses a door locking device which includes an elongated rail rotatably mounted at one side of a doorframe so that it can be rotated across that doorframe. The rail has a projection which is designed to extend into a locking device contained within the door, so that the door can be locked to the rail, preventing the door from opening in an unwanted manner. Although such a device appears to have many advantages, it has the disadvantages of requiring that a special locking device be mounted in the door with which it is used, and of its rail being mounted in or near the doorframe with which it is to be used, and it appears to be a device which could be relatively easily broken by burglars or vandals.